Lexan Cover For Solar Panels

The discussion of covers for solar panels comes up on the
various forums from time to time. Some locations are prone to hail.
Here in central FL, tropical storms and hurricanes are a potential threat 6
months out of every year. Lexan (polycarbonate) is the same material
used for bullet proof glass. Even a thin piece won't break when bent.
It can be fatigued and it will eventually break, but this material is far
from brittle.

It would be possible to put spacers between the cover and the panels.
Allowing airflow, and some room for the cover to flex when taking a
significant impact.

But there's a potential issue, it isn't the same optical quality of the
expensive glass used for solar panels. Is it really that big of a
deal? Watch the video.

There was a suggestion that the angle of the Lexan had
something to do with the shadow. To show that the shadow never goes away,
despite the relative angle to the sun, I made the following video.

The 1/4" thick Lexan cover made about a 20% difference in the output of the
panel. This was a new piece of material, and the performance will only
get worse with time as the cover ages. Lexan is clear, it does have a
slight tint to the material. This tint creates a visible shadow, and
apparently blocks enough of the light spectrum to reduce the output of the
solar panels.

I don't consider these covers as a
viable option. The good news is solar panel companies perform hail
impact testing. They can take some abuse as is.

There are some benefits in choosing a slightly smaller panel. They
are lighter, easier to carry up the ladder, no more expensive per watt than
the larger panels, and if one is damaged during a storm, it's less of an
impact (pun intended) to remove it from the system. I particularly
like the Kyocera 130W and 135W panels.